Multicenter prospective cross-sectional study of CD patients, its aim is the construction of an objective and reproducible system for evaluation of Transmural healing in Crohn's Disease (CD).

Primary objective : Objective definition of depth or grade of transmural healing in relation to radiologic signs observed during Magnetic Resonance Enterography (MRE) in CD

Number of patients : 210 patients, in 14 sites (only one investigator per site), 15 patients per site, 5 patients per grade of transmural healing based on the appraisal of a local reader pair (a gastroenterologist and a radiologist).

Recruitment period : 2 years

Primary Endpoint : Objective definition of depth or grade of transmural healing in relation to radiologic signs observed during Magnetic Resonance Enterography (MRE) in CD

Secondary Endpoints :

• To analyze intra- and inter-observer variability of radiological findings.
• To analyze intra- and inter-observer variability of TH definitions in CD.

Inclusion Criteria:

• ≥ 18 years of age
• Patient diagnosed with CD for more than 6 months with histological confirmation available in his medical record.
• Indication for MRE based on routine clinical practice validated by the treating physician
• Any CD treatment will be authorized, such as biologicals (infliximab, adalimumab, vedolizumab, ustekinumab…), or immunomodulators (azathioprine, 6-mercaptopurine, methotrexate…).
• The subjects sign and date a written, informed consent form and any required privacy authorization prior to the initiation of the study.
• A subject can be enrolled into the study only if the grade of TH (assessed by the LRP) corresponding to the subject is not already fulfilled.

Exclusion Criteria:

• Pregnancy during the study
• People unable to give consent (because of their physical or mental state)
• Absence of written consent
• Ulcerative colitis or unclassified IBD
• Specific postsurgical settings: ileoanal anastomosis, ileostomy or colostomy.
• Less than 3 evaluable ileocolic segments or more than 3 resected ileocolonic segments (not counting ileocecal valve)
• Severe obstructive symptoms
• Symptomatic intra-abdominal abscess
• Contraindication for MRI
• Isolated perianal disease without luminal location
• MRE images of poor quality, based on previously defined criteria

Patients diagnosed with CD for more than 6 months with histological confirmation available in his medical record, with an indication for MRE based on routine clinical practice validated by the treating physician